Security system and method to detect concealed items

• US 10,210,730 B2
• Filed: 03/31/2017
• Issued: 02/19/2019
• Est. Priority Date: 03/31/2017
• Status: Active Grant

• Current Assignee: United States Secretary of Homeland Security
• Original Assignee: The Government Of The United States Of America, As Represented By The Secretary Of Homeland Security
• Inventors: Fry, Mark A., Smith, Barry T.
• Primary Examiner(s): Findley, Christopher G
• Application Number:
  US15/475,798
• Publication Number:
  US 20180286202A1
• Time in Patent Office: 690 Days
• Field of Search: None
• CPC Class Codes: G06T 5/20 using local operators
• CPC Class Codes: G06T 7/20 Analysis of motion motion estimation for coding, decoding, compressing or decompressing digital video signals H04N19/43, H04N19/51
• CPC Class Codes: G06T 7/70 Determining position or orientation of objects or cameras camera calibration G06T7/80
• CPC Class Codes: G06V 20/52 Surveillance or monitoring of activities, e.g. for recognising suspicious objects recognising microscopic objects G06V20/69
• CPC Class Codes: G08B 13/19697 Arrangements wherein non-video detectors generate an alarm themselves
• CPC Class Codes: H04N 7/183 for receiving images from a single remote source
• CPC Class Codes: H04N 7/188 Capturing isolated or intermittent images triggered by the occurrence of a predetermined event, e.g. an object reaching a predetermined position signal generation from motion picture films H04N5/253

Abstract

A security system to detect a concealed item carried by a traveler in motion, the security system includes a camera configured to capture an image series of the traveler in a Eulerian or Lagrangian frame of reference, wherein the captured image series contains motions generated by the concealed item; an alarm system configured to produce an alert signal; and an electronic control unit. The electronic control unit is configured to magnify motions generated by the concealed item to generate perceptible motions, provide an output image series that contains the perceptible motion, detect characteristic kinematic behaviors of the concealed item from the output image series, measure characteristic kinematic quantities of the characteristic kinematic behaviors, determine a presence of the concealed item from the characteristic kinematic quantities, and activate the alarm system to produce the alert signal.

Claims

1. A security system to detect a concealed item carried by a traveler in motion, the security system comprising:

a camera configured to capture an image series of the traveler in one of an Eulerian frame of reference and a Lagrangian frame of reference, wherein the captured image series contains motions generated by the concealed item;

an alarm system that produces an alert signal; and

an electronic control unit configured to;

magnify the motions generated by the concealed item to generate frame of reference perceptible motions;

detect characteristic kinematic behaviors of the perceptible motions;

measure characteristic kinematic quantities of the characteristic kinematic behaviors;

determine a presence of the concealed item from the characteristic kinematic quantities; and

activate the alarm system to produce the alert signal.

2. The security system of claim 1, wherein the electronic control unit is further configured to:

extract a pixel value time series for each image of the input image series; and

apply a magnification function to the pixel value time series;

wherein the magnification function depends on spatial frequencies of the pixel value time series.

3. The security system of claim 2, wherein the magnification function provides a maximum amplification when the spatial frequencies are lower than a critical spatial frequency and an attenuation when the spatial frequencies exceed the critical spatial frequency.

4. The security system of claim 2, wherein the electronic control unit is further configured to apply a bandpass filter to the pixel value time series.

5. The security system of claim 4, wherein the bandpass filter has a pass band that is centered on a key frequency of the traveler in motion.

6. The security system of claim 5, wherein the bandpass filter is constructed with a first first-order lowpass infinite impulse response filter having a first cutoff frequency and a second first-order lowpass infinite impulse response filter having a second cutoff frequency.

7. The security system of claim 1, wherein the characteristic kinematic behaviors include rigid body motions.

8. The security system of claim 7, wherein the characteristics kinematic quantities include moments of the rigid body motions.

9. The security system of claim 1, wherein the electronic control unit is further configured to select a specific zone of interest for each image of the captured image series.

10. The security system of claim 1, wherein the electronic control unit is further configured to alert authorities in response to the alert signal.

11. A method to detect a concealed item carried by a traveler in motion, the method comprising:

capturing an image series of the traveler in one of an Eulerian frame of reference and a Lagrangian frame of reference, via a camera, wherein the captured image series contains motions generated by the concealed item;

magnifying the motions generated by the concealed item, via the processing circuitry, to generate perceptible motions;

detecting characteristic kinematic behaviors of the perceptible motions, via the processing circuitry;

measuring characteristic kinematic quantities of the characteristic kinematic behaviors, via processing circuitry;

determining a presence of the concealed item from the characteristic kinematic quantities, via processing circuitry; and

producing an alert signal via an alarm system.

12. The method of claim 11, further comprising:

extracting pixel value time series for each image of the captured image series, via the processing circuitry; and

applying a magnification function to the pixel value time series, via processing circuitry;

wherein the magnification function depends on spatial frequencies of the pixel value time series.

13. The method of claim 12, wherein applying the magnification function further includes providing a maximum amplification, via the processing circuitry, when the spatial frequencies are lower than a critical spatial frequency and an attenuation when the spatial frequencies exceed the critical spatial frequency.

14. The method of claim 12, wherein extracting the pixel value time series further includes applying a bandpass filter to the pixel value time series, via the processing circuitry.

15. The method of claim 14, wherein the bandpass filter has a pass band that is centered on a key frequency of the traveler in motion.

16. The method claim 15, wherein the bandpass filter is constructed with a first first-order lowpass infinite impulse response filter having a first cutoff frequency and a second first-order lowpass infinite impulse response filter having a second cutoff frequency.

17. The method of claim 11, wherein the characteristic kinematic behaviors include rigid body motions.

18. The method of claim 17, wherein the characteristics kinematic quantities include moments of the rigid body motions.

19. The method of claim 11, further includes selecting a specific zone of interest for each image of the input image series, via the processing circuitry.

20. The method of claim 11, further includes alerting the authorities, via a network interface of the electronic control unit, in response to the alert signal.